Method and apparatus for detecting data on a photographic recording medium

ABSTRACT

Disclosed is a method and apparatus for detecting data recorded at a predetermined position on a photographic recording medium. The apparatus includes signal-light projection means for projecting light to the predetermined position on the photographic recording medium and signal-light detection means positioned to receive and detect the intensity of the signal light leaving the photographic recording medium. The magnitude of the signal light leaving the photographic recording medium is affected by the data recorded at the predetermined position. In its preferred embodiment, the apparatus is an exposed-frame detector for detecting whether a particular frame on a photographic recording medium having a plurality of discrete frames has been exposed. The apparatus includes mask means for producing a black border on each frame, the black border being opaque and reflecting the signal light at a reduced predetermined intensity. The signal-light detection means measures the reduced intensity of signal light and can inform the operator, though conventional electric circuitry, that the particular frame has already been imaged.

United States Patent 1 1111 3,873,213 Plumadorf 1 1 Mar. 25, 1975 METHOD AND APPARATUS FOR DETECTING DATA ON A PHOTOGRAPHIC RECORDING MEDIUM [75] Inventor: John David Plumadorf, Westfield,

Mass.

[73] Assignee: Scott Paper Company, Delaware County, Pa.

[22] Filed: Apr. 8, 1974 [21] Appl. No.: 459,197

[52] U.S. Cl 356/209, 250/561, 250/566,

[51] Int. Cl. GOln 21/48, G03b 27/52 [58] Field of Search 355/41; 356/209; 250/561, 250/566, 568, 569

[56] References Cited UNITED STATES PATENTS 2,760,404 8/1956 King 350/171 3,240,114 3/1966 Jonker ct a1. 356/71 3,299,272 1/1967 Furukawa ct a1 250/561 3,418,905 12/1968 Dietz 250/559 3,469,105 9/1969 Stasey 250/561 3,523,495 8/1970 Giedd 354/76 3,549,254 12/1970 Muir 355/41 UX 3,594,087 7/1971 Miranda 356/203 3,597,045 8/1971 Mathisen 356/71 3,623,024 11/1971 Hamilton 350/35 3,685,912 8/1972 Graig 356/157 Primary Examiner-Ronald L. Wibert Assistant Examiner-Richard A. Rosenberger Attorney, Agent, or FirmR. Duke Vickrey; William .1. Foley [57] ABSTRACT Disclosed is a method and apparatus for detecting data recorded at a predetermined position on a photographic recording medium. The apparatus includes signal-light projection means for projecting light to the predetermined position on the photographic recording medium and signal-light detection means positioned to receive and detect the intensity of the signal light leaving the photographic recording medium. The magnitude of the signal light leaving the photographic recording medium is affected by the data recorded at the predetermined position. In its preferred embodiment, the apparatus is an exposed-frame detector for detecting whether a particular frame on a photographic recording medium having a plurality of discrete frames has been exposed. The apparatus includes mask means for producing a black border on each frame, the black border being opaque and refleeting the signal light at a reduced predetermined intensity. The signal-light detection means measures the reduced intensity of signal light and can inform the operator, though conventional electric circuitry, that the particular frame has already been imaged.

11 Claims, 3 Drawing Figures METHOD AND APPARATUS FOR DETECTING DATA ON A PHOTOGRAPHIC RECORDING MEDIUM BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to systems for photographically storing data, and more particularly, to an apparatus for detecting data recorded at a predetermined position on a electrophotographic film.

Description of the Prior Art Stimulated by the costs incurred in storing the everincreasing volume of documentary material which is presently being generated, considerable effort has been expended in the design and development of various electrophotographic and other data storage and retrieval systems. Particular emphasis has been placed on the design of microphotographic systems which may be used to decrease the physical bulk of such stored materials without sacrificing file retrieval and/or copy reproduction capabilities.

A particularly desirable microphotographic copying system has been developed which records data from documents upon discrete frames of a multi-frame microfiche This type of microfiche is a transparent elec trophotographic film having a substrate of transparent material, such as five mil polyester base, with a thin transparent conductive layer coated thereon as well as an additional outer layer of a suitable transparent photoconductive material. Any number of various films in the art may be utilized with equal efficiency in this type of apparatus, such as those disclosed in US Pats. Nos. 3,290,147; 3,314,788; and 3,615,404, which are herein incorporated by reference.

An operator places a microfiche within the photocopying machine and sequentially records images of documents on individual frames in the microfiche. The number of frames in a microfiche might be sixty or more, and it is common for the operator to record document information on several of the frames and then remove the microfiche for storage until later information is desired to be recorded on other frames of the microfiche. When the partially imaged microfiche is re turned to the copying machine for further recording of document information, the operator must selectively position the first unimaged frame which sequentially follows the last imaged frame onto the imaging optical axis. While this can be done by the operator noting the position of the last imaged frame and pressing an indexing control button to move the next frame into position, this method is time consuming and subject to error. If the operator erroneously selects a previously imaged frame and proceeds to project a new image upon that frame, he could superimpose additional data upon the frame, perhaps resulting in obliteration of the previous image.

Therefore, it is an object of the invention to provide an apparatus for detecting information, in general, recorded on a film and particularly information which in dicates whether a selected frame has already been imaged.

SUMMARY OF THE INVENTION The apparatus of the invention employs the light transmitting and reflecting properties of the photoconductive layer of a microfiche. Specifically, the surface of the photoconductive layers used in transparent electrophotographic recording mediums specularly reflect a beam of light from the surface when undeveloped with toner particles. However, when the photoconductive surface has been electrostatically charged and exposed to a light pattern and developed with toner particles, such as carbon particles, the dark toned areas significantly reduce the light transmission and reflecting properties of the photoconductive layer. Thus, the magnitude or intensity of the light reflected from or passed through the toned area on the photoconductive layer will be significantly reduced.

The invention includes signal-light projection means for projecting light to a predetermined position on a selected frame of the photographic recording medium, and signal-light detection means positioned to receive and detect the intensity of the signal light coming from the photographic recording medium. The preferred form of the invention includes means within a photographic recording apparatus associated with the invention for causing the predetermined position of each frame to be toned upon imaging the frame, whereby the intensity of the signal light received by the signal-light detection means is reduced if the frame has been exposed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagramatic sectional view showing an electrophotographic recording apparatus within which the invention is employed.

FIG. 2 is a plan view of a microfiche useful with the invention, illustrating several exposed frames.

FIG. 3 is an enlarged partial view of an imaged frame of the microfiche illustrated in FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION The electrophotographic recording apparatus in which the present invention is preferably used is diagramatically illustrated in FIG. 1. The apparatus includes an enclosure I0 having top panel with a trans parent copyboard 15 upon which the document 16 to be copied is placed. Within the enclosure 10, is a projection lamp 17, which reflects a light off of document 16 onto mirror 14 where the image is projected along imaging optical axis 18, through a lens 19 mounted in a charge and image module 13, and onto the selected frame of a microfiche 12. Within the charge and image module 13 is a'corona charging needle 20, which is charged by aconventional high voltage potential (not shown) to produce a corona and electrostatically charge the photoconductive layer of the frame positioned against the module 13. The charge and image module 13 includes mask 21, forming an opening 22 against which the selected frame on the microfiche 12 is positioned. After charging, the light image from the document is projected onto the photoconductive layer of the frame being imaged to pattern dissipate the charge and produce a latent electrostatic image. The imaged frame can be rendered visible by applying electrostatically charged developer particles, such as carbon particles, to the imaged surface where the particles adhere in the image pattern to the surface ofthe photoconductive layer by electrostatic attraction. A permanent visible image can be obtained. for example. by using developer particles which can be heat fused to the photoconductive layer and subjecting it to a heat application step. The developing steps are most conveniently accomplished at a location away from the charge and image module 13 by any conventional developing means.

The preferred form of the invention is an exposedframe indicator which includes dark mask means 27 at the border regions of the copyboard 15 for producing a dark border region around the imaged frame of the microfiche. FIG. 3 illustrates an imaged frame of the microfiche 12 of FIG. 2, where 31 generally indicates the boundaries of this particular frame, 32 illustrates the dark border formed by imaging the document through a copyboard 15 having dark mask means 27, and 33 illustrates data recorded from the document. The invention further includes light projection means 23 which directs a beam of light 24, onto dark border region 32 of the imaged frame and a signal-light detector 26 which detects the reflected signal light from the .surface of the photoconductive layer. The signal-light detection means 26 can be provided by a conventional photocell which can measure the intensity oflight it receives.

Although many arrangements of the signal-light projection means 23 and signal-light detection means 26 can be employed, it is preferred that the projection means 23 is located adjacent the border of the copyboard 15 so that the signal light beam 24 is assured of being projected onto the predetermined position of the frame where the dark border 32 will be developed. Also, it is preferred that the signal-light detecting means 26 be mounted within the charge and image module 13 at a position off of the imaging axis 18 so that it does not interfere with imaging of the microfiche. This arrangement can be satisfactorily accomplished because the surface of the photoconductive layer spccularly reflects light at an angle which directs the reflected beam of light out of the imaging axis 18.

In operation, the highly reflective surface of an undeveloped photoconductive layer reflects a relatively strong light beam to the signal-light means 26. But, after development of a particular frame, whereupon dark toner particles are deposited and fused to form a dark border region 32, the intensity of the reflected signal light is significantly diminished, and the reduced signal is detected by the detector means 26. An electric signal dependent upon the magnitude of the signal light received by the signal-light detection means 26' can be produced by conventional means for purposes of informing the operator that the frame has already been exposed. The operator can be informed by a warning light and/or electrical control means to prevent inadvertent re-imaging of an already imaged frame.

Although the preferred embodiment of the invention isas described above, it will be obvious to one skilled in the art that many variations within the scope of the invention can be practiced. For example, the data recorded upon an imaged frame does not have to be in the form of a dark border, although this is preferable in that it also produces an attractive arrangement on the imaged microfiche and it permits wide latitude in placing the signal-light projection and detection means 23 and 26. The data could also be in the form of a single dark mark imaged at the predetermined position 25 on the frame, or a number of marks or particular figures (including numerals and letters) which would produce a varying intensity or magnitude reflected signal light, the intensity or magnitude of which depends upon the number of or type of figures. With this latter arrangement, it would be possible to detect such information as frame number or other identifying information,

Additionally, the positions of the signal-light projection means 23 and signal-light detection means 26 could be altered, although these particular positions are highly advantageous for the microphotographic recording apparatus illustrated in FIG. 1. The projection means 23 and detection means 26 could be in reverse position. The detection means 26 could also be outside of the module 13, or even on the opposite side of the film 12, in which case the signal-light detection means would determine the intensity of the light beam 24 passing through the film 12. However, in an apparatus of the type illustrated in FIG. 1, where the microfiche 12 is commonly positioned in a carrier (not shown), it is not convenient to pass the light through the film because of interference by the carrier. A further arrangement which could be utilized is the use of multiple signal-light projection means, each projecting a beam to a different predetermined position 25 on the frame, with either one or a plurality of signal-light detection means receiving the reflected light.

It is also possible to advantageously employ the invention where the photographic recording medium reflects light diffusely, rather than spccularly or the signal-light projection means 23 could be an ordinary lamp casting light in all directions rather than in a beam. However, it is far more convenient in avoiding noise interference from outside sources of light if the signal light is projected in a beam and the light is specularly reflected. A spccularly reflected beam oflight will form a cone shape beam with equal light intensity at all positions in the cone for equal distances from the reflecting surface. Therefore, the placement of the signallight detection means 26 is not limited to a single line, but can be placed over a larger area.

What is claimed is:

1. In an apparatus for selectively imaging discrete frames on a photographic recording medium having a plurality of frames thereon and upon which imaging is accomplished by projecting an illuminated image from a document through a lens and onto the selected frame on the photographic recording medium, an exposedframe detector comprising:

signal-light projection means for projecting light to a predetermined position on each frame of the photographic recording medium; signal-light detection means positioned to receive the signal light leaving the photographic recording-medium and for detecting the magnitude of the signal light leaving the photographic recording medium; and t means within the apparatus for causing the predetermined position of each frame to change its optical properties upon developing an image on the frame. whereby the magnitude of the signal light received be the signal-light detection means is reduced,

2. The exposed-frame detector according to claim 1. wherein the means for causing the predetermined position on each frame to change its optical properties upon developing an image on the frame is provided by dark mask means around the border of a copyboard upon which the document is placed. the dark mask means producing a dark border on each frame.

3. The exposed-frame detector according to claim I, wherein the signal light is projected in a beam and is specularly reflected from the surface of the photographic medium in a reflected conical shaped beam, and the signal-light detection means is positioned in the path of the reflected beam.

4. Apparatus for detecting data recorded at a predetermined position on each frame of a multi-frame electrophotographic film having a photoconductive layer which specularly reflects light at one intensity if it has not been developed with dark toner particles and at a lesser intensity if it has dark toner particles developed on it, the apparatus comprising:

signal-light projection means for projecting a beam of light to the predetermined position of a selected frame, whereby the light is reflected from the surface of the photoconductive layer in a reflected beam and the amount of light reflected is dependent upon the data recorded at the predetermined position; and

signallight detection means positioned in the path of the reflected beam for detecting the intensity of the reflected signal-light.

5. In an apparatus for selectively imaging discrete frames on a transparent electrophotographic microfiche, comprising document holding means for holding a document to be imaged on the microfiche, means for projecting the image of the document along an optical axis to a selected frame on the microfiche, and a charge and image module positioned on the optical axis and including a lens and electrostatic charging element, an apparatus for detecting data recorded in a predetermined position on each frame of the microfiche comprising:

signal-light projection means mounted adjacent the border of the document holding means for projecting a signal light in a beam through the lens and onto the predetermined position of the selected frame, whereby the light is specularly reflected from the surface of the microfiche in a beam, the intensity of which is dependent upon the data recorded at the predetermined position; and

signal-light detecting means for detecting the intensity of the reflected signal light and positioned in the path of the reflected beam and within the charge and image module.

6. Apparatus for detecting data according to claim 5, wherein the signal light detecting means is positioned off of the optical axis, whereby it does not interfere with imaging of the microfiche.

7. Apparatus according to claim 6, wherein the data to be detected is a dark border surrounding the selected frame, and the apparatus further includes dark mask means surrounding the document holding means, the mask means producing on opaque border on the frame upon imaging and developing of the frame.

8. A method of detecting whether a frame has been on the photographic recording medium, the method comprising the steps of:

projecting a signal image onto a predetermined position of a frame when imaging the frame, the signal image becoming opaque upon developing the frame; projecting a signal light to the predetermined position on the frame of the photographic recording medium, whereby the signal light is reflected from the surface of the predetermined position at one intensity if the frame has not been imaged and at a lesser intensity if the frame has been imaged; and

measuring with light detection means the intensity of the signal light reflected from the predetermined position to thereby determine whether the frame has been exposed.

9. Method according to claim 8, wherein the signal data projected onto the predetermined position of each frame is a dark border surrounding the frame.

10. Method for detecting data recorded at a predetermined position on each frame of a multi-frame electrophotographic film having a photoconductive layer which specularly reflects light at one intensity if it has not been developed with dark toner particles and at a lesser intensity if it has dark toner particles developed on it, the method comprising the steps of:

projecting a beam of light to the predetermined position of a selected frame, whereby .the light is reflected from the surface of the photoconductive layer in a reflected beam and the amount of light reflected is dependent upon the data recorded at the predetermined position; and

measuring the amount of the reflected light with light detection means positioned in the path of the reflected beam.

11. In an apparatus for selectively imaging discrete frames on a transparent electrophotographic microfiche, comprising document holding means for holding a document to be imaged on the microfiche, means to project the image of the document along an optical axis to a selected frame on the microfiche, and a charge and image module positioned on the optical axis and including a lens and electrostatic charging element,

the method of detecting data recorded in a predetermined position on each frame of the microfiche,

comprising the steps of:

projecting a signal light from a position adjacent the border of the document holding means through a lens and onto the predetermined position of the selected frame, whereby the light is specularly reflected from the surface of the microfiche in a reflected beam, the intensity of which is dependent upon the data recorded at the predetermined position; and

measuring the intensity of the light with signal-light detecting means positioned in the path of the reflected beam and within the charge and image FORM PO-IOSO (IO-69) UNTTED STATES PATENT OFFICE QEH EQATE 0F QGECTIQN 5,873,215 Dated March 25, 1975 Patent No.

John David Plumadore Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as Shown below:

-- John David Plumadore gigned and gealed this ninth D a Of September 19 75 [SEAL] A ties t:

RUTH C. MASON Arresting Officer C. MARSHALL DANN (mmnissimzer nj'lau'ms and Trademarks USCOMM-DC 60376-P69 U.S. GOVERNMENT PRINTING OFFXCE: 8 69. 93 O 

1. In an apparatus for selectively imaging discrete frames on a photographic recording medium having a plurality of frames thereon and upon which imaging is accomplished by projecting an illuminated image from a document through a lens and onto the selected frame on the photographic recording medium, an exposedframe detector comprising: signal-light projection means for projecting light to a predetermined position on each frame of the photographic recording medium; signal-light detection means positioned to receive the signal light leaving the photographic recording medium and for detecting the magnitude of the signal light leaving the photographic recording medium; and means within the apparatus for causing the predetermined position of each frame to change its optical properties upon developing an image on the frame, whereby the magnitude of the signal light received be the signal-light detection means is reduced.
 2. The exposed-frame detector according to claim 1, wherein the means for causing the predetermined position on each frame to change its optical properties upon developing an image on the frame is provided by dark mask means around the border of a copyboard upon which the document is placed, the dark mask means producing a dark border on each frame.
 3. The exposed-frame detector according to claim 1, wherein the signal light is projected in a beam and is specularly reflected from the surface of the photographic medium in a reflected conical shaped beam, and the signal-light detection means is positioned in the path of the reflected beam.
 4. Apparatus for detecting data recorded at a predetermined position on each frame of a multi-frame electrophotographic film having a photoconductive layer which specularly reflects light at one intensity if it has not been developed with dark toner particles and at a lesser intensity if it has dark toner particles developed on it, the apparatus comprising: signal-light projection means for projecting a beam of light to the predetermined position of a selected frame, whereby the light is reflected from the surface of the photoconductive layer in a Reflected beam and the amount of light reflected is dependent upon the data recorded at the predetermined position; and signal-light detection means positioned in the path of the reflected beam for detecting the intensity of the reflected signal-light.
 5. In an apparatus for selectively imaging discrete frames on a transparent electrophotographic microfiche, comprising document holding means for holding a document to be imaged on the microfiche, means for projecting the image of the document along an optical axis to a selected frame on the microfiche, and a charge and image module positioned on the optical axis and including a lens and electrostatic charging element, an apparatus for detecting data recorded in a predetermined position on each frame of the microfiche comprising: signal-light projection means mounted adjacent the border of the document holding means for projecting a signal light in a beam through the lens and onto the predetermined position of the selected frame, whereby the light is specularly reflected from the surface of the microfiche in a beam, the intensity of which is dependent upon the data recorded at the predetermined position; and signal-light detecting means for detecting the intensity of the reflected signal light and positioned in the path of the reflected beam and within the charge and image module.
 6. Apparatus for detecting data according to claim 5, wherein the signal light detecting means is positioned off of the optical axis, whereby it does not interfere with imaging of the microfiche.
 7. Apparatus according to claim 6, wherein the data to be detected is a dark border surrounding the selected frame, and the apparatus further includes dark mask means surrounding the document holding means, the mask means producing on opaque border on the frame upon imaging and developing of the frame.
 8. A method of detecting whether a frame has been exposed in an apparatus for selectively imaging discrete frames on a photographic recording medium having a plurality of frames thereon and upon which imaging is accomplished by projecting an illuminated image from a document through a lens and onto the selected frame on the photographic recording medium, the method comprising the steps of: projecting a signal image onto a predetermined position of a frame when imaging the frame, the signal image becoming opaque upon developing the frame; projecting a signal light to the predetermined position on the frame of the photographic recording medium, whereby the signal light is reflected from the surface of the predetermined position at one intensity if the frame has not been imaged and at a lesser intensity if the frame has been imaged; and measuring with light detection means the intensity of the signal light reflected from the predetermined position to thereby determine whether the frame has been exposed.
 9. Method according to claim 8, wherein the signal data projected onto the predetermined position of each frame is a dark border surrounding the frame.
 10. Method for detecting data recorded at a predetermined position on each frame of a multi-frame electrophotographic film having a photoconductive layer which specularly reflects light at one intensity if it has not been developed with dark toner particles and at a lesser intensity if it has dark toner particles developed on it, the method comprising the steps of: projecting a beam of light to the predetermined position of a selected frame, whereby the light is reflected from the surface of the photoconductive layer in a reflected beam and the amount of light reflected is dependent upon the data recorded at the predetermined position; and measuring the amount of the reflected light with light detection means positioned in the path of the reflected beam.
 11. In an apparatus for selectively imaging discrete frames on a transparent electrophotographic microfiche, comprising document holding means for holding a document to be imaged on the microfiche, means to projEct the image of the document along an optical axis to a selected frame on the microfiche, and a charge and image module positioned on the optical axis and including a lens and electrostatic charging element, the method of detecting data recorded in a predetermined position on each frame of the microfiche, comprising the steps of: projecting a signal light from a position adjacent the border of the document holding means through a lens and onto the predetermined position of the selected frame, whereby the light is specularly reflected from the surface of the microfiche in a reflected beam, the intensity of which is dependent upon the data recorded at the predetermined position; and measuring the intensity of the light with signal-light detecting means positioned in the path of the reflected beam and within the charge and image module. 